Centering device for conducting liquefied arc-extinguishing gas to a highpressure reservoir



Dec. 5, 1967 c. KE LER 3,356,810

CONDUCTI CENTERING DEVICE FOR LIQUEFlED ARC-EXTINGUISHING GAS TO AHIGHPRESSURE'REZSERVOIR Filed March 51, 1965 2 Sheets-Sheet 1 C.KESSLER.

Dec. 5, 1967 (ENTERING DEVICE FOR CONDUCTING LIQUEFLEJD ARC-EXTINGUISHING GAS TO A HIGHPRESSURE RESERVOIR 2 Sheets-Shes; 2

Filed March 31, 1965 INVENTOR Claus Kessler By MM A. w

ATTORNEY FIG.3.

WITNESSES United States Patent 3,356,810 CENTERING DEVICE FOR CONDUCTINGLIQUE- FIED ARC-EXTINGUISHING GAS TO A HIGH- PRESSURE RESERVOIR ClausKessler, Berlin-Dahlem, Germany, assignor to Siemens-SchuckertwerkeAktiengesellschaft, Erlangen, Germany, a corporation of Germany FiledMar. 31, 1965, Ser. No. 444,189 2 Claims. (Cl. 200-148) This inventionrelates generally to circuit-interrupting structures utilizing anarc-extinguishing gas, and more particularly, to an improved centeringdevice for centering the flow of liquefied gas, under low ambienttemperature conditions, through the high-pressure gas-conducting tube tothe grounded high-pressure gas-reservoir chamher.

A general object of the present invention is to provide an improvedliquefied-gas centering device to prevent the deposition of conductingparticles on the inner side walls of the high-pressure gas supply tube.There may be two kinds of contaminants, one consisting of metallicflakes, or cuttings from castings which must be machined, and are notfully washed away by shop procedures. Secondly, if the drying of thesulfur-hexafiuoride (SP gas is not kept under control, an excess ofmoisture in the top high-pressure reservoir will condense as waterdroplets and with a resultant chemical reaction with the SP gas willlead to conducting water droplets.

Another object of the invention is the provision of an improvedliquefied-gas return device to prevent the hazard of flashover along theinsulating high-pressure gas supply tube, by providing a centeringdevice, including a centering trough, which will guide any liquefied gasto the centerline of the high-pressure gas supply tube and therebyprevent the deposition of conducting particles along the inner sidewalls of the insulating high-pressure gas supply tube.

Some high-voltage power circuit breakers using sulfur-hexafiuoride (SPgas as an interrupting medium have had the hazard of electrical failuresof the highpressure gas-supply line from the high-pressure gas-reservoirchamber at ground potential to the high-pressure gas-reservoir chamberat line or high potential. These high-pressure gas supply lines are madeof insulating tubing and are subjected to relatively high electricalstresses. Such a high-pressure gas supply line conducts gas from thehigh-pressure gas reservoir chamber at ground potential to thehigh-pressure gas reservoir chamber at high or line potential, andreturns liquid condensate to ground potential, where it is revaporizedby suitable auxiliary heating equipment. The exact cause of suchfailures of such high-pressure gas supply tubes has not been determined,but it is suspected that the condensate in the reservoir at highpotential may pick up conducting particles, and that while flowing downthe high-pressure gassupply tube may deposit some of these conductingparticles on the inside wall of the gas supply tube. Traces of suchdeposits have been found on some high-pressure gas supply tubes. Thiscondition is probably of most importance in the vicinity of thehigh-potential parts, where the voltage gradient along the high-pressuresupply tube has the highest value.

It is, accordingly, an object of the present invention to prevent thedeposition of the liquid condensate which may carry such conductingparticles on the inner side walls of the high-pressure gas supply tubeto prevent the resultant hazard of voltage fiasho-ver along the axiallength of the supply tube.

Further objects and advantages will readily become apparent upon readingthe following specification, taken in conjunction with the drawings, inwhich:

Patented Dec. 5, 1967 FIGURE 1 is -a side elevational view of one poleof a three-pole high-voltage gas-type circuit-interrupting structureembodying the principles of the present invention; and,

FIGS. 2 and 3 collectively show a composite vertical sectional viewtaken substantially along the line IIII of FIG. 1, the upper figureportion FIG. 2 indicating the gas-flow conditions into the rotatableinterrupting arm during interrupting conditions, and the lower figureportion FIG. 3 indicating the closed position of the main blast valve inthe closed-circuit position of the interrupter.

Referring to the drawings, and more particularly to FIG. 1 thereof, thereference numeral 1 designates a three-pole gas-blast type ofhigh-voltage circuit interrupter suitable for high voltages, say 500 kv.or 700 kv. As is well known by those skilled in the art, for the highervoltages it is merely necessary to incorporate additional interruptingheads 2 serially into the circuit to Withstand the high voltage in theopen-circuit position of the device.

As illustrated in FIG. 1, the interrupting heads 2 are supported at theupper ends of upstanding insulating columns 3, the lower ends of whichare supported upon a horizontally-extending base framework 4. As shown,the base framework 4 comprises a plurality of heavy structural steelmembers 5-7 supporting a longitudinally-extending high-pressure gasreservoir tank 10 of sulfur hexafiuoride (SP gas and suitable compressorequipment 12. Insulating angle supports 15 may additionally be providedto enable the interrupting heads 2, which are of relatively heavy metal,to withstand wind-loading forces.

A current-transformer structure 19 is supplied in series with the linecircuit L L to effect a measurement of the current flow through theinterrupter 1. Although FIG. 1 merely shows a side elevational view ofone pole-unit A only, it is to be understood that normally there arethree such pole-units in side-by-side relation to enable the control ofa three-phase transmission circuit.

As more fully set forth in detail in US. patent application filed June12, 1964, Ser. No. 374,708, (W.E. 34,561) by Roswell C. Van Sickle,entitled Interrupting Structures and Operating Mechanisms forCompressed-Gas Circuit Interrupters, and assigned to the WestinghouseElectric Corporation, disposed within each of the interrupting heads 2is a rotatable interrupting arm 25 carrying a pair of serially-relatedinterrupting units 26 at the opposite free ends thereof. Theinterrupting arm 25 is hollow, as at 25a, and permits the transmissiontherethrough of a blast of high-pressure gas from a high-pressuregas-reservoir chamber 27 through a horizontallymovable blast valve 30,which is actuated to the open and closed positions by suitableblast-valve operating mech anisms, generally designated by the referencenumeral 32, and illustrated in detail in the aforesaid patentapplication.

During the opening operation the rotatable interrupting arm 25 causesthe separation of two movable contacts 34 from stationary contactstructures, not shown, which are disposed at the interior ends ofterminal bushings 36, which extend laterally into the interior of theinterrupting heads 2. Thus, in the closed-circuit position of thedevice, the two serially-related movable contacts 34, which are providedat opposite extremities of the rotating interrupting arm 25, makecontacting engagement with the stationary contact structures, not shown,which are disposed at the fixed interior ends of the terminal bushings36 within the interior 40 of the interrupting heads 2.

Simultaneously with the rotative opening movement of the interruptingarm 25, there is effected an opening of the blast-valve mechanism 32 toeffect inward opening movement of the blast-valve structure 30 andconsequently an outward flow of high-pressure gas, as indicated by thearrows 33 in FIG. 2. In the closed-circuit position of the interrupter,and in the fully opened-circuit position of the interrupter, theblast-valve 30 is maintained in an outward closed position, as shown inFIG. 3. In this position of the blast-valve 30, the gas flow is' halted,and, as is customary, during the closing operation of the interrupter,the blast-valve 30 is likewise maintained in the closed-circuitposition.

In a gas-type circuit interrupter using certain gases, such as sulfurhexafiuoride (SE gas, during low-temperature ambient conditions, thereis the distinct possibility of liquefaction of the high-pressure SF gasdisposed within the high-pressure high-voltage reservoir chamber 27.Such liquefied SP gas, or liquid condensate may run downwardly bygravity flow along the high-pressure gas supply tube 50 to the lowergrounded high-pressure reservoir chamber 10. As pointed out above, thereis the possibility that the liquid SE condensate will pick up conductingparticles in the chamber 27 and cause them to be deposited along theinner side walls of the insulating high-pressure gas supply tube 50. Ifthis continues, there results the distinct hazard of votalge flashoveraxially along the insulating high-pressure tube 50. It is, accordingly,an object of the present invention to avoid the possibility of suchdeposition by centering the downward flow of the liquefied SEcondensate. This will avoid the cumulative deposition of conductingparticles along the inside walls of the insulating high-pressure supplytube 50 and will consequently avoid such hazard of voltage flashover. Asshown in FIG. 3, it will be noted that there is provided a 90 elbow 60,which may form a part of a casting 61, which interconnects the upper endof the high-pressure supply tube 50 with the high-pressure highvoltagereservoir 27. As a result, any liquid SE condensate, which accumulateswithin a recess portion 70 of the casting 27, will be centered bycausing it to flow through a trough, or grooved portion 72 of the elbowconnection 60 to fall vertically downwardly through the center of theinsulating high-pressure tube 50, as indicated by the liquid droplets80. These liquefied droplets 80, in avoiding contact with the innerwalls 50a of the highpressure supply tube 50, will drop down into thegrounded high-pressure horizontally-extending tank 10.

Although not particularly visible in FIG. 1 of the drawings, in fact thelongitudinally-extending high-pressure gas-supply reservoir 10 at groundpotential is tipped slightly, so that one end 10a thereof is at a lowerlevel than the other end. As a result, any condensate 80 which fallsdownwardly into the high-pressure grounded reservoir chamber 10 willflow to one end 10a thereof, and will be vaporized by a heater 84, whichis disposed internally of the high-pressure reservoir 10 and isconnected, through a thermostat 86, to a suitable electrical supplycircuit 88. Suitable insulation 90 is provided around the tank 10 andaround an upstanding bellows portion 92 thereof to prevent theapplication of low-ambient temperatures from causing a liquefaction ofthe high-pressure SP gas provided in the lower chamber 10.

The thermostat 86 will cause an energizing of the heater 84 undercertain temperature conditions, which will result in a vaporization ofany condensate 80, which is collected at the lower end of the tank 10.

Although the present invention has been described in connection withsulfur hexafluoride (SP gas, it is to be clearly understood that thesame structure could be provided for other arc-extinguishing gases,which are susceptible of liquefaction under low-ambient temperatureoperating conditions.

The upstanding column 3 serves as a means of transmitting relativelylow-pressure gas within the region 40 downwardly and through aconnection 99 into a compressor 100, which may be responsive to certaindifierential density instruments 102, so that when the pressure buildsup too much within the region 40, or similarly, if the high pressurewithin the reservoirs 10, 27 drops too low, the compressor 100 will bestarted up and thereby effect a compression of high-pressure SE gas intothe high-pressure reservoirs 10, 27.

Although there has been illustrated and described a specific structure,it is to be clearly understood that the same was merely for the purposeof illustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing from the spiritand scope of the inevntion.

I claim as my invention:

1. In a high-voltage compressed-gas type of circuit interrupter havingseparable contacts and means utilizing a high-pressure blast of gas toeffect extinction of the arc established at said contacts, saidinterrupter further having a high-voltage high-pressure gas-reservoirchamber and a grounded high-pressure gas reservoir chamber with aninterconnecting highpressure insulating supply tube therebetween, thecombination therewith of a centeringtrough means for centering the flowof liquid condensate under low-ambient temperature conditions throughsaid high-pressure insulating supply tube, whereby the deposition ofentrained conducting particles in the condensate on the inner side wallsof the insulating supply tube will be avoided, and thereby the hazard ofvoltage flashover eliminated.

2. The combination according to claim 1, wherein the centering-troughmeans comprises a elbow connection of metal attached to the high-voltagehigh-pressure gas-reservoir chamber.

References Cited UNITED STATES PATENTS 761,760 6/1904 Chesney 174-112,673,232 3/1954 Silsby 17430 3,060,294 10/ 1962 Leeds 200-148 FOREIGNPATENTS 1 14,5 73- 4/ 1926 Switzerland.

ROBERT S. MACON, Primary Examiner.

1. IN A HIGH-VOLTAGE COMPRESSED-GAS TYPE OF CIRCUIT INTERRUPTER HAVINGSEPARABLE CONTACTS AND MEANS UTILIZING A HIGH-PRESSURE BLAST OF GAS TOEFFECT EXTINCTION OF THE ARC ESTABLISHED AT SAID CONTACTS, SAIDINTERRUPTER FURTHER HAVING A HIGH-VOLTAGE HIGH-PRESSURE GAS-RESERVOIRCHAMBER AND A GROUNDED HIGH-PRESSURE GAS RESERVOIR CHAMBER WITH ANINTERCONNECTING HIGH-PRESSURE INSULATING SUPPLY TUBE THEREBETWEEN, THECOMBINATION THEREWITH OF A CENTERINGTROUGH MEANS FOR CENTERING THE FLOWOF LIQUID CONDENSATE UNDER LOW-AMBIENT TEMPERATURE, CONDITIONS THROUGHSAID HIGH-PRESSURE INSULATING SUPPLY TUBE, WHEREBY THE DEPOSITION OFENTRAINED CONDUCTING PARTICLES IN THE CONDENSATE ON THE INNER SIDE WALLSOF THE INSULATING SUPPLY TUBE WILL BE AVOIDED, AND THEREBY THE HAZARD OFVOLTAGE FLASHOVER ELIMINATED.